Pill taken before, after sex may prevent HIV

An HIV prevention pill taken by gay men before and after sex reduced the risk of virus transmission by 86 percent, according to the results of a clinical trial released Tuesday. Truvada contains HIV treatment drugs tenofovir and emtricitabine, and is made by Gilead Sciences in California. In the study Truvada was taken up to one day before sex and the two days after.

The study, led by the French National HIV research agency ANRS, was presented at the Conference on Retroviruses and Opportunistic Infections (CROI) in Seattle. Until now, Truvada as a preventive measure has been prescribed only as a once-a-day regimen, not one that could be effective if taken around the time of sex. While the latest evidence on the technique known as pre-exposure prophylaxis, or PrEP, is not enough to change guidelines, it was welcomed as a novel approach to HIV prevention.